Reactivation of immune responses against Mycobacterium tuberculosis by boosting with the CpG oligomer in aged mice primarily vaccinated with Mycobacterium bovis BCG

Background Mycobacterium bovis bacillus Calmette Guerin (BCG) vaccine, which has been inoculated to more than one billion people world-wide, has significant effect in preventing tuberculous meningitis and miliary tuberculosis (TB) in neonate and early childhood. However, BCG fails to adequately protect against pulmonary TB and reactivation of latent infections in adults. To overcome this problem, adequate booster is urgently desired in adult who received prior BCG vaccination, and appropriate animal models that substitute human cases would be highly valuable for further experimentation.